Merge the v0.8.6 feature batch and release hardening.\n\nIncludes the full #373-#380/#382-#402 milestone scope, version bump to 0.8.6, secure /share temp-file handling, Windows-safe self-update replacement, and CI portability fixes.\n\nRemote PR checks passed on the final head before merge.
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DeepSeek TUI Architecture
This document provides an overview of the DeepSeek TUI architecture for developers and contributors.
Current boundary note (v0.8.6):
crates/tuiis still the live end-user runtime for the TUI, runtime API, task manager, and tool execution loop.- Other workspace crates are being split out incrementally, but they are not yet the sole runtime source of truth.
- The LSP subsystem (
crates/tui/src/lsp/) is fully wired into the engine's post-tool-execution path (core/engine/lsp_hooks.rs), providing inline diagnostics after every edit_file/apply_patch/write_file. - The swarm agent system was removed in v0.8.5 in favour of sub-agents (agent_spawn) and RLM (rlm_query). No swarm references remain in the active codebase.
High-Level Overview
┌─────────────────────────────────────────────────────────────────┐
│ User Interface │
│ ┌─────────────────┐ ┌─────────────────┐ ┌────────────────┐ │
│ │ TUI (ratatui) │ │ One-shot Mode │ │ Config/CLI │ │
│ └────────┬────────┘ └────────┬────────┘ └────────┬───────┘ │
└───────────┼─────────────────────┼────────────────────┼──────────┘
│ │ │
▼ ▼ ▼
┌─────────────────────────────────────────────────────────────────┐
│ Core Engine │
│ ┌─────────────────────────────────────────────────────────┐ │
│ │ Agent Loop (core/engine.rs) │ │
│ │ ┌─────────┐ ┌─────────────┐ ┌──────────────────────┐ │ │
│ │ │ Session │ │ Turn Mgmt │ │ Tool Orchestration │ │ │
│ │ └─────────┘ └─────────────┘ └──────────────────────┘ │ │
│ └─────────────────────────────────────────────────────────┘ │
└─────────────────────────────────────────────────────────────────┘
│ │ │
▼ ▼ ▼
┌─────────────────────────────────────────────────────────────────┐
│ Tool & Extension Layer │
│ ┌──────────┐ ┌──────────┐ ┌─────────┐ ┌────────────────┐ │
│ │ Tools │ │ Skills │ │ Hooks │ │ MCP Servers │ │
│ │ (shell, │ │ (plugins)│ │ (pre/ │ │ (external) │ │
│ │ file) │ │ │ │ post) │ │ │ │
│ └──────────┘ └──────────┘ └─────────┘ └────────────────┘ │
└─────────────────────────────────────────────────────────────────┘
│ │ │
▼ ▼ ▼
┌─────────────────────────────────────────────────────────────────┐
│ Runtime API + Task Management │
│ ┌─────────────────────────────┐ ┌──────────────────────────┐ │
│ │ HTTP/SSE Runtime API │ │ Persistent Task Manager │ │
│ │ (runtime_api.rs) │ │ (task_manager.rs) │ │
│ └─────────────────────────────┘ └──────────────────────────┘ │
└─────────────────────────────────────────────────────────────────┘
│ │
▼ ▼
┌─────────────────────────────────────────────────────────────────┐
│ LLM Layer │
│ ┌──────────────────────────────────────────────────────────┐ │
│ │ LLM Client Abstraction (llm_client.rs) │ │
│ │ ┌─────────────────┐ ┌─────────────────────────────┐ │ │
│ │ │ DeepSeek Client │ │ Compatible Client (DeepSeek)│ │ │
│ │ │ (client.rs) │ │ (client.rs) │ │ │
│ │ └─────────────────┘ └─────────────────────────────┘ │ │
│ └──────────────────────────────────────────────────────────┘ │
└─────────────────────────────────────────────────────────────────┘
Module Organization
Entry Point
main.rs- CLI argument parsing (clap), configuration loading, entry point routing
Core Components
core/- Main engine componentsengine.rs- Engine state, operation handling, message processingengine/turn_loop.rs- Streaming turn loop and tool execution orchestrationengine/capacity_flow.rs- Capacity guardrail checkpoints and interventionssession.rs- Session state managementturn.rs- Turn-based conversation handlingevents.rs- Event system for UI updatesops.rs- Core operations
Configuration
config.rs- Configuration loading, profiles, environment variablessettings.rs- Runtime settings management
Workspace Crates
crates/tools- Shared tool invocation primitives, including tool result/error/capability types used by the TUI runtime.crates/agent- Model/provider registry (ModelRegistry) for resolving model IDs to provider endpoints.crates/app-server- HTTP/SSE + JSON-RPC app server transport for headless agent workflows.crates/config- Config loading, profiles, environment variable precedence, CLI runtime overrides.crates/core- Agent loop, session management, turn orchestration, capacity flow guardrails.crates/execpolicy- Approval/sandbox policy engine for tool execution decisions.crates/hooks- Lifecycle hooks (stdout, jsonl, webhook) for pre/post tool events.crates/mcp- MCP client + stdio server for Model Context Protocol tool servers.crates/protocol- Request/response framing and protocol types.crates/secrets- OS keyring integration for API key storage.crates/state- SQLite thread/session persistence layer.crates/tui-core- Event-driven TUI state machine scaffold.
LLM Integration
client.rs- HTTP client for DeepSeek's documented OpenAI-compatible Chat Completions APIllm_client.rs- Abstract LLM client trait with retry logicmodels.rs- Data structures for API requests/responses
DeepSeek API Endpoints
DeepSeek exposes OpenAI-compatible endpoints. The CLI uses:
https://api.deepseek.com/v1/chat/completions- normal and streaming model turnshttps://api.deepseek.com/v1/models- live model discovery and health checks
https://api.deepseek.com/v1 is accepted for OpenAI SDK compatibility, and
https://api.deepseek.com/beta can be configured for beta-only features such as
strict tool mode, chat prefix completion, and FIM completion. The public
DeepSeek docs do not document a Responses API path for this workflow; the engine
drives turns through Chat Completions.
Tool System
tools/- Built-in tool implementationsmod.rs- Tool registry and common typesshell.rs- Shell command executionfile.rs- File read/write operationstodo.rs- Checklist tools plus legacy todo aliasestasks.rs- Model-visible durable task, gate, background shell, and PR-attempt toolsgithub.rs- Read-only GitHub context and guarded comment/closure tools backed byghautomation.rs- Model-visible scheduling tools overAutomationManagerplan.rs- Planning toolssubagent.rs- Sub-agent spawning (replaces the removedagent_swarmsurface)spec.rs- Tool specificationsrlm.rs- Recursive Language Model (RLM) tool — sandboxed Python REPL withllm_query()helpers
Extension Systems
mcp.rs- Model Context Protocol client for external tool serversskills.rs- Plugin/skill loading and executionhooks.rs- Pre/post execution hooks with conditions
User Interface
-
tui/- Terminal UI components (ratatui-based)app.rs- Application state and message handlingui.rs- Event handling, streaming state, and rendering logicapproval.rs- Tool approval dialogclipboard.rs- Clipboard handlingstreaming.rs- Streaming text collector
-
ui.rs- Legacy/simple UI utilities
LSP Integration
lsp/- Post-edit diagnostics injection (#136)mod.rs-LspManager— lazy per-language transport pool + configclient.rs-StdioLspTransport— JSON-RPC over stdio withdidOpen/didChange/publishDiagnosticsdiagnostics.rs- Diagnostic types, severity, and HTML-block rendererregistry.rs- Language detection and default server map (rust-analyzer, pyright, gopls, clangd, typescript-language-server)- Wired into the engine via
core/engine/lsp_hooks.rs— called after every successful edit
Security
sandbox/- macOS sandboxing supportmod.rs- Sandbox type definitionspolicy.rs- Sandbox policy configurationseatbelt.rs- macOS Seatbelt profile generation
Utilities
utils.rs- Common utilitieslogging.rs- Logging infrastructurecompaction.rs- Context compaction for long conversationspricing.rs- Cost estimationprompts.rs- System prompt templatesproject_doc.rs- Project documentation handlingsession.rs- Session serializationruntime_api.rs- HTTP/SSE runtime API (deepseek serve --http)runtime_threads.rs- Durable thread/turn/item store + replayable event timelinetask_manager.rs- Durable queue, worker pool, task timelines and artifacts
Data Flow
Interactive Session
- User input received in TUI
- Input processed by
core/engine.rs - Message sent to LLM via
llm_client.rs - Response streamed back, parsed in
client.rs - Tool calls extracted and executed via
tools/ - Hooks triggered before/after tool execution
- Results aggregated and sent back to LLM
- Final response rendered in TUI
Crash Recovery + Offline Queue
- Before sending user input, the TUI writes a checkpoint snapshot to
~/.deepseek/sessions/checkpoints/latest.json - Startup remains fresh by default; prior sessions are resumed explicitly via
--resume/--continue(orCtrl+Rin TUI) - While degraded/offline, new prompts are queued in-memory and mirrored to
~/.deepseek/sessions/checkpoints/offline_queue.json - Queue edits (
/queue ...) are persisted continuously so drafts and queued prompts survive restarts - Successful turn completion clears the active checkpoint and writes a durable session snapshot
- Agent/Yolo turns also take pre/post-turn side-git workspace snapshots under
~/.deepseek/snapshots/<project_hash>/<worktree_hash>/.git;/restore Nandrevert_turnrestore file state without changing conversation history or the user's.git
Tool Execution
- LLM requests tool via
tool_usecontent block - Tool registry looks up handler
- Pre-execution hooks run
- Approval requested if needed (non-yolo mode)
- Tool executed (possibly sandboxed on macOS)
- Post-execution hooks run
- Result metadata is retained on runtime item records
- LSP post-edit hook (v0.8.6): if the tool was
edit_file/apply_patch/write_fileand LSP is enabled, the engine runsrun_post_edit_lsp_hook()to collect diagnostics - Diagnostics flush (v0.8.6): before the next API request,
flush_pending_lsp_diagnostics()injects any collected errors as a synthetic user message - Result returned to agent loop
Background Tasks
- Client enqueues task (
/task add ...orPOST /v1/tasks) task_manager.rspersists task + queue entry under~/.deepseek/tasks- Worker picks queued task (bounded pool), transitions to
running - Task creates/uses a runtime thread and starts a runtime turn
runtime_threads.rspersists thread/turn/item records + monotonic event sequence- Timeline/tool summaries/artifact references are persisted incrementally
- Checklist state, verifier gates, PR attempts, and guarded GitHub events are applied from tool metadata to the active task
- Final state (
completed|failed|canceled) is durable and queryable via TUI/API
Model-visible durable task tools are a surface over this same manager. They do
not introduce a parallel work system: task_create enqueues normal tasks,
checklist_* updates task-local progress, task_gate_run and completed
task_shell_wait attach verification evidence, and automation runs enqueue
ordinary durable tasks.
Runtime Thread/Turn Timeline
- API/TUI creates or resumes a thread (
/v1/threads*) - Turn starts on the thread (
/v1/threads/{id}/turns) - Engine events are mapped to item lifecycle events (
item.started|item.delta|item.completed) - Interrupt/steer operations apply to the active turn only
- Compaction (auto/manual) is emitted as
context_compactionitem lifecycle - Clients replay history and resume with
/v1/threads/{id}/events?since_seq=<n>
Durable Schema Gates
session_manager.rs,runtime_threads.rs, andtask_manager.rsembedschema_versionon persisted records.- On load, newer schema versions are rejected with explicit errors instead of silently truncating/overwriting data.
- This allows safe forward migrations and prevents corruption when binaries and stored state are out of sync.
Extension Points
Adding a New Tool
- Create handler in
tools/ - Register in
tools/registry.rs - Add tool specification (name, description, input schema)
Adding an MCP Server
- Configure in
~/.deepseek/mcp.json - Server auto-discovered at startup
- Tools exposed to LLM automatically
Creating a Skill
- Create skill directory with
SKILL.md - Define skill prompt and optional scripts
- Place in
~/.deepseek/skills/
Adding Hooks
Configure in ~/.deepseek/config.toml:
[[hooks]]
event = "tool_call_before"
command = "echo 'Running tool: $TOOL_NAME'"
Key Design Decisions
- Streaming-first: All LLM responses stream for responsiveness
- Tool safety: Non-YOLO mode requires approval for destructive operations, including side-effectful MCP tools
- Extensibility: MCP, skills, and hooks allow customization without code changes
- Cross-platform: Core works on Linux/macOS/Windows, sandboxing macOS-only
- Minimal dependencies: Careful dependency selection for build speed
- Local-first runtime API: HTTP/SSE endpoints are intended for trusted localhost access and are served by the
crates/tuiruntime today
Configuration Files
~/.deepseek/config.toml- Main configuration/etc/deepseek/managed_config.toml- Optional managed defaults layer (Unix)/etc/deepseek/requirements.toml- Optional allowed-policy constraints (Unix)~/.deepseek/mcp.json- MCP server configuration~/.deepseek/skills/- User skills directory~/.deepseek/sessions/- Session history~/.deepseek/sessions/checkpoints/- Crash checkpoint + offline queue persistence~/.deepseek/snapshots/- Side-git pre/post-turn workspace snapshots for/restoreandrevert_turn~/.deepseek/tasks/- Background task records, queue, timelines, artifacts~/.deepseek/audit.log- Append-only audit events for credential + approval/elevation actions